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Amazon rainforests green‐up with sunlight in dry season
Author(s) -
Huete Alfredo R.,
Didan Kamel,
Shimabukuro Yosio E.,
Ratana Piyachat,
Saleska Scott R.,
Hutyra Lucy R.,
Yang Wenze,
Nemani Ramakrishna R.,
Myneni Ranga
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl025583
Subject(s) - environmental science , rainforest , dry season , moderate resolution imaging spectroradiometer , canopy , amazon rainforest , leaf area index , eddy covariance , vegetation (pathology) , atmospheric sciences , tree canopy , ecosystem , carbon cycle , phenology , enhanced vegetation index , biometeorology , hydrology (agriculture) , normalized difference vegetation index , ecology , satellite , geology , biology , vegetation index , medicine , geotechnical engineering , pathology , engineering , aerospace engineering
Metabolism and phenology of Amazon rainforests significantly influence global dynamics of climate, carbon and water, but remain poorly understood. We analyzed Amazon vegetation phenology at multiple scales with Moderate Resolution Imaging Spectroradiometer (MODIS) satellite measurements from 2000 to 2005. MODIS Enhanced Vegetation Index (EVI, an index of canopy photosynthetic capacity) increased by 25% with sunlight during the dry season across Amazon forests, opposite to ecosystem model predictions that water limitation should cause dry season declines in forest canopy photosynthesis. In contrast to intact forests, areas converted to pasture showed dry‐season declines in EVI‐derived photosynthetic capacity, presumably because removal of deep‐rooted forest trees reduced access to deep soil water. Local canopy photosynthesis measured from eddy flux towers in both a rainforest and forest conversion site confirm our interpretation of satellite data, and suggest that basin‐wide carbon fluxes can be constrained by integrating remote sensing and local flux measurements.